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3.3 Operation of the GK-405 Readout Box
The GK-405 Vibrating Wire Readout is made up of two components:
the Readout Unit, consisting of a Windows Mobile handheld PC running the GK-405
Vibrating Wire Readout Application
the GK-405 Remote Module which is housed in a weather-proof enclosure and connects
to the vibrating wire sensor by means of:
1) Flying leads with alligator type clips when the sensor cable terminates in bare wires or,
2) by means of a 10 pin connector..
The two components communicate wirelessly using Bluetooth
communications protocol. The Readout Unit can operate from the cradle of the Remote
Module (see Figure 3) or, if more convenient, can be removed and operated up to 20 meters
from the Remote Module
For further details consult the GK405 Instruction Manual.
3.4. Measuring Temperatures
Each Vibrating Wire Displacement Transducer is equipped with a thermistor for reading
temperature. The thermistor gives a varying resistance output as the temperature changes.
Usually the white and green leads are connected to the internal thermistor. All readout
boxes will read the thermistor and display temperature in C automatically
1. If using an ohmmeter connect to the two green and white thermistor leads coming from
the transducer. (Since the resistance changes with temperature are so large, the effect
of cable resistance is usually insignificant.)
2. Look up the temperature for the measured resistance in Table B-1 (Appendix B).
Alternately the temperature could be calculated using Equation B-1 (Appendix B). For
example, a resistance of 3400 ohms equivalent to 22° C. When long cables are used
the cable resistance may need to be taken into account. Standard 22 AWG stranded
copper lead cable is approximately 14.7/1000' or 48.5/km, multiply by 2 for both
directions.
Figure 3 GK405 Readout Unit
®
, a reliable digital
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